Analysis and application of transformer models in the ATP program for the study of ferroresonance

Ferroresonance is a phenomenon of complex nature which should be carefully analyzed so that preventive measures could be taken before its appearance may cause damages to electric power installations. There are some configurations as well as winding connections in transformers that may lead to the appearance of ferroresonance. In particular, middle-voltage underground networks formed by insulated cables, supplying unloaded or slightly loaded transformers. In order to identify the phenomenon and the nature of overvoltages, simulation is normally performed in EMTP-type programs. The ATP (Alternative Transients Program) has been chosen in this work. Several transformer models have been implemented in ATP, in particular the SATURABLE, BCTRAN and Hybrid (XFMR) models. The XFMR has been recently implemented in ATP and is still not yet widely known by the scientific community. Several simulations are performed with these models for typical configurations of distribution networks.